July 18, 2013

Some alfalfa and livestock producers may be questioning the nutrient value of their first cutting alfalfa. Several factors likely contributed to low nutrient levels that are showing up in poor forage test values or thinner replacement heifers and calves.

In wet years, such as we had in late spring, the moisture stimulates extra growth and extra water in the plant, which tends to dillute nutrient concentration. Plus, a wetter forage tends to pass through the animal's digestive system faster so some nutrients aren't digested.

Several other factors also may be at play this year. Most alfalfa was simply cut later than usual due to all the rain delays. It may not have looked more mature, but it still was older and contained extra fiber.

Cloudy weather also may have played a role. Soils warmed up slowly and a lack of sunshine may have reduced the amount of nutrients produced. High humidity or cloudy weather also may have led to slow drying after cutting.  Until alfalfa dries down to less than 50% moisture, it continues to burn off nutrients. When it takes alfalfa longer to dry, desirable nutrients are burned away, leaving behind the less desirable fiber.

While it's difficult to tell which of these factors caused low nutrient content in a given field, understanding the potential causes can help you compensate for it in future years.

Bruce Anderson
Extension Forage Specialist